In this study

a 12-degree bending-torsion dynamic model for the double-helical gear system was established to reveal the influence of tooth surface wear on the dynamics

which considered some factors such as tooth surface wear

meshing errors

meshing stiffness and etc.. The changes in the vibration displacement and vibration speed of the herringbone gear under different running times of the herringbone gear system were studied. A new double-helical testbed was set-up

which consisting of a test machine and test specimens. The test rig measured the vibration acceleration under different input torque and speed for double-helical gear transmission. The changes of vibration acceleration amplitude for double-helical gear transmission under different working conditions were discussed. The results show that

the vibration acceleration amplitude increases rapidly with the increase of the input speed if the input torque is constant

and the vibration acceleration amplitude does not change with the increase of the input torque if the input speed is constant. Moreover

vibration acceleration amplitude of each component of the double-helical gear transmission first decreases and then increases with the increase numbers of running.